Peristaltic-type pump



May 3, 1966 c. E. RENN PERISTALTIC-TYPE. PUMP 2 Sheets-Sheet 1 Filed March 31, 1964 INVENTDR.

CHARLES E. RE/V/V BY .1, 4M ,L 4M

y 3, 6 c. E. RENN I 3,249,059

PERI STALTIC-TYPE. PUMP Filed March 31, 19 64 2 Sheets-Sheet 2 2a 3 52 48 4? 35 if? 38 INVENTOR. CHAR L E s E. REA N A 7' TORNE Y5 United States Patent 3,249,059 PERISTALTlC-TYPE PUMP Charles E. Reno, Baltimore, Md, assignor to Everpure, Inc, Qalr'oroolt, 111., a corporation of Nevada Filed Mar. 31, 1964, Ser. No. 356,193 9 Ciaims. (Cl. 1ti3149) This invention relates to pumps and more particularly to a new and improved peristaltic-type pump.

Peristaltic-type pumps are of the type adapted momentarily to compress successive portions of a length of collapsible tubing for moving a fluid through the latter in a manner whereby the active parts of the pump do not contact the fluid being pumped. This type of pump is quite often characterized by a cylindrical housing containing a planetary roller assembly and a length of collapsible tubing fitted against the inner curved wall of the housing for being compressed along successive portions of the tubing by planetary rollers for forcing fluid forwardly of these rollers through the tubing and for creating a suction efiect rearwardly of the rollers thereby continuously to pump fluid through the tubing.

It is a primary object of the present invention to provide a pump of the type described which includes new and improved means for supporting and guiding the planetary roller assembly which compresses the length of collapsible tubing.

It is another object of the present invention to provide a pump of the type described which includes a housing of new and improved construction thereby adapting the pump for ready attachment to and detachment from a length of tubing.

Another object of the present invention is the provision of a pump of the type described which is adapted to be detached or separated from the associated length of collapsible tubing without disassembly of the planetary roller assembly or removal of the roller assembly from the pump housing.

Yet another object of the present invention is the provision of a pump of the type described which may be readily adapted to accommodate collapsible tubing of different diameters and wall thicknesses.

Even another object of the present invention is the provision of a peristaltic-type pump which includes new and improved means for supporting the planetary rollers and their central drive roller thereby to obviate rotatably mounting these rollers on individual central bearings.

Another object of the present invention is the provision of a pump of the type described which is adapted to be readily coupled with a number of other pumps of this invention whereby all of the pumps may be driven by a common power source.

Still another object of the present invention is the provision of a pump which is of simplified construction thereby having the attendant advantage of low cost mauufacture.

These and other objects and advantages of the invention will become apparent from the following specification describing a preferred embodiment of the invention which is illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is an exploded perspective view of a preferred embodiment of the pump of this invention;

FIG. 2 is a side elevation of the pump with one of the planetary roller spider plates and one of the housing walls removed for better illustration of the planetary roller assembly;

FIG. 3 is a side elevation of the pump; and

FIG. 4 is a section taken along lines 4-4 of HG. 3.

Referring to the drawings, the peristaltic-type pump of this invention will be seen to comprise a housing, gen- 3,249,059 Patented May 3, 1966 erally designated 10, which includes a pair of identical rectangular plates or walls 12 and 14. The wall plates are spaced in parallel relation by a block 15 which is secured between opposed lower marginal portions of the plates by means of a pair of pins 16 and 17, the pins being snugly received in aligned apertures in block 15 and in plates 12 and 14. Plates 12 and 14 are provided with respective central openings 19 and 20 defining circular tracks 21 and 2.2. It will be understood that openings 19 and 20 are of the same diameter and have their central axes ooaxial. Plates 12 and 14 are also provided with respective apertures 24 and 25 adjacent their upper corners for receiving pins 27 and 28 which are provided for securing an upper center housing block 59 in place in a manner to be explained hereinbelow.

A planetary roller assembly, generally designated 32 (FIG. 1), primarily includes a central drive roller 33, four planetary rollers 34 and a pair of circular spider plates 35 and 36. The central drive roller is non-rotatably mounted on a drive shaft 38, which shaft is adapted to be coupled with a suitable drive motor, such as an electric motor, for operation of the pump in a manner to be described below.

Each planetary roller 34 includes a central bore 40 opening at opposite ends of the planetary roller for receiving a pin 41 having its opposite ends secured in suitable apertures in the spider plates. It will be noted that bores 40 are of somewhat greater diameter than the outside diameter of pins 41 thereby resulting in a somewhat loose or sloppy fit of the planetary rollers on respective pins. As will become apparent herein, the planetary rollers need not be accurately journaled on the pins or provided with bearings as the planetary rollers are actually guided for rotation about their own axes and in a circular path by engagement with tracks 21 and 22 and the cylindrical surface of the central drive roller. In effect, pins 41 maintain the planetary rollers in circumferential spaced relation and hold the spider plates in parallel spaced-apart relation.

Spider plates 35 and 36 are provided with respective central openings 42 and 43 (FIG. 4) for freely receiving drive shaft 38, which drive shaft has a diameter somewhat lcss than the diameter of the central drive roller. Engagement of opposed annular portions of spider plates 35 and 36 around the central openings therein with opposite ends of drive roller 33 prevent axial movement of the latter when both spider plates are assembled in place.

As best seen in FIGS. 2 and 3, the planetary rollers engage tracks 21 and 22 and the cylindrical surface of central drive roller 33. More specifically opposite end portions only of planetary rollers 34 roll along respective circular tracks 21 and 22 and are thereby maintained in simultaneous frictional engagement with central drive roller 33. The portions of the planetary rollers intermediate their opposite ends contact the tube for collapsing the same as will be explained below.

When mounting the planetary rollers in the pump housing, it is necessary to assemble the planetary rollers within the circular tracks before securing both spider plates in place as the latter have a diameter greater than the diameter of the circular tracks. As best noted in FIG. 4, engagement of opposed outer marginal portions of the spider plates with outer angular portions of plates 12 and 14 around the central openings therein prevents separation of the planetary roller assembly from the pump housing.

The planetary rollers are guided for rotation about their own axes and in a circular path described by movement of these axes by engagement of the planetary rollers with the circular tracks 21 and 22 and with the central drive roller, and this movement of the planetary rollers 3 is brought about by rotating the central roller by attaching an electric motor, for example, to drive shaft 38. Slippage between the central roller and the planetary rollers is minimized by providing the central roller with a pair of friction rings 45 and 46 (FIG. 4) which are received in annular recesses provided in the central roller. Rings 45 and 46 are preferably made of a resilient material snugly fitted in the annular recesses in the driving roller and provided with an outside diameter greater than theoutside diameter of the latter for frictionally engaging the planetary rollers thereby substantially to prevent slippage between the latter and the drive roller. Rings 45 and 46 may be standard O-rings.

Upper center block 30, which has a width equal to the width of block 15, is provided on its underside with a generally semi-cylindrical bearing surface 48. Block 30 is provided with a pair of small apertures 49 and is detachably secured in place between plates 12 and 14 by aligning apertures 49 with apertures 24 and 25 and then inserting pins 27 and 28 in place in the aligned apertures. Block 30 is provided with an integral rib-like portion 50 which serves as a finger gripping portion for placing block between plates 12 and 14 and for removing the block from between these plates.

When block 30 is mounted in place as just described, the central axis of bearing surface 48 is in co-axial relationship with the central axes of circular openings 19 and 20. Bearing surface 48 has a radius which exceeds the radii of tracks 21 and 22 by an amount which is generally the same as twice the wall thickness of a length of collapsible tubing 52,'which tubing is adapted to be momentarily compressed along successive portions thereof for having a fluid pumped therethrough. -Or in other words, the radius of bearing surface 48 exceeds the sum of the radius of the circular path of the rollers and the radius of one of the planetary rollers by an amount which is generally the same as twice the wall thickness of tubing 52. Preferably, the radius of bearing surface 48 exceeds the radii of the tracks by an amount which is just slightly less, e.g., .015 inch, than twice the wall thickness of a tubing 52 having a wall thickness of .0625 inch. This construction insures complete closing or sealing of the tubing by the planetary rollers for positive and improved operation of the pump. It will be understood that the dimensions given above are for purposes of illustration only and are not to be taken as limiting the invention in any way.

By the provision of housing block 30, which is removable in a plane perpendicular to the axes of the planetary rollers, the pump of this invention may be readily clamped to or unclamped from the length of collapsible tubing '52.

When attaching or clamping the pump to the length of tubing, block 30 is removed by withdrawing pins 27 and '28. Tubing 52 is then inserted between plates 12 and 14 and looped or trained ,over two or three of the planetary rollers. *Block 30 is then secured in place by means of pins 27 and 28, which brings about engagement of bearing surface 48 with the looped portion of the tubing for holding the latter in a generally semi-circular shape. It will be apparent that the pump may be attached to or detached from the tubing without disturbing connections at opposite ends of the tubing, if such is the case.

It should be realized that the pump of the invention may be readily adapted for accommodating collapsible tubing of different outside diameters and wall thicknesses. This is accomplished in one way by providing additional housing blocks 30 having semi-cylindrical bearing surfaces 48 of different diameters for accommodating a particular size of tubing. Alternatively, block 30 may be provided with a bearing surface designed to accommodate the largest tubing to be compressed and a number of arcuate inserts of progressively decreasing radii may be provided'for being inserted against the bearing surface, wherein each insert is designed to accommodate a particular size of tubing.

Rotation of the drive roller causes the planetary rollers to rotate about their own axes and in a circular path for momentarily compressing the tubing along successive portions of the latter for forcing a fluid in the tubing forwardly of the rollers through the tubing and for creating a suction fluid rearwardly of the rollers. As the planetary rollers revolve about their own axes in a direction opposite to the direction of their movement in their circular path and as the planetary rollers are driven by the central drive roller, the planetary rollers roll along the inside surface of the looped portion of tubing without tending to drag or pull the latter through the pump housing. It will be apparent that the direction of flow through the tubing may be reversed by reversing the direction of rotation of the drive roller.

It should be noted that by the provision of four planetary rollers and a semi-cylindrical bearing surface, i.e., a bearing surface extending through a arc, at least two planetary rollers are in compressing engagement with the collapsible tubing at all times. This feature generally improves the operation of the pump and makes the same self-priming and anti-siphoning.

As mentioned above, the use of central bearings for mounting planetary rollers 34 is obviated as these rollers are mounted by the central drive roller and the circular tracks which co-operate to drive the planetary rollers about their own central axes and in a circular paththe pins carried by the spider plates serve only to maintain the planetary rollers in circumferential spaced relation, i.e., to prevent the planetary rollers from bunching up. Further, it will be realized that central drive roller 33 need not .be rotatably supported on a central hearing as the same is held in concentric relationship with the tracks by contact with the planetary rollers as long as at least three planetary rollers are provided.

It should also be noted that as planetary rollers 34 are in constant engagement with circular tracks 21 and 22, centrifugal force acting on the planetary rollers does not change-the amount of pressure between the rollers and the tubing. In other words, the pressure between the rollers and tubing is constant regardless of the speed of rotation of the planetary roller arrangement. This feature accounts for increased life of the tubing.

The pump of this invention may be constructed from a wide variety of materials since the pump itself does not come into contact with the fluid being pumped. The entire pump may be made of metal or the pump housing may be made of plastic with the rollers constructed from paper reinforced phenolic plastic, for example. In all forms of construction, driven shaft 38 and pins 41 are preferably made of metal. The collapsible tubing is preferably made of plastic or rubber.

It will be apparent that a number of pumps 10 of this invention may be driven by a common power source by mounting the pumps adjacent one another in axial alignment, coupling adjacent ends of drive shafts 38, and connecting one of the drive shafts with the power source. Alternatively, this multiple pumping operation might be brought about by employing a single continuous drive shaft 38 having a length sufiicient to extend through the drive rollers of all the aligned pumps to be driven by the single power source.

While the invention has been shown in but one form it will be obvious to those skilled in the art that it is not to be so limited but on the contrary it is susceptible of various changes and modifications without departing from the spirit and scope of the appended claims.

I claim:

1. A peristaltic-type pump for momentarily compressing successive portions of a length of collapsible tubing, said pump comprising, a housing having a pair of parallel spaced wall portions each of which is configured for defining a circular track, said tracks having their central axes co-axial and perpendicular to said wall portions, a plurality of planetary rollers extending axially of said circular tracks and having their opposite end portions in respective rolling engagement with the tracks, a central roller co-axial with said axes and in simultaneous engagement with all of said planetary rollers thereby to cooperate with said tracks for driving the planetary rollers about their respective central axes and along a circular path described by movement of the last mentioned axes, each of said rollers having a tube contacting portion intermediate said end portions, said housing including a portion provided with a bearing surface which extends along at least a portion of the length of said tracks in parallel spaced relation from the same, a length of collapsible tubing having a section thereof in contact with said bearing surface along a portion of the length of the latter, the radius of said bearing surface being greater than the sum of the radius of said path and the radius of one of said planetary rollers at the tube contacting portion thereof by an amount which is generally the same as twice the wall thickness of the collapsible tubing to be compressed.

2. A peristaltic-type pump for momentarily compress ing successive portions of a length of collapsible tubing, said pump comprising, a housing having a pair of parallel spaced wall portions each of which is configured for defining a circular track, said tracks having their central axes co-axial and perpendicular to said wall portions, a plurality of planetary rollers extending axially of said circular tracks and having their opposite end portions in respective rolling engagement with the tracks, a central roller co-axial with said axes and in simultaneous engagement with all of said planetary rollers thereby to cooperate with said tracks for driving the planetary rollers about their respective central axes and along a circular path described by movement of the last mentioned axes, each of said rollers having a tube contacting portion intermediate said end portions, spider plate means in engagement with respective planetary rollers thereby to maintain the latter in substantial uniform spaced relation, said housing including a portion provided with a bearing surface which extends along at least a portion of the length of said tracks in parallel spaced relation from the same, a length of collapsible tubing having a section thereof in contact with said bearing surface along a portion of the length of the latter, the radius of said bearing surface being greater than the sum of the radius of said path and the radius of one of said planetary rollers at the tube contacting portion thereof by an amount which is generally the same as twice the wall thickness of the collapsible tubing to be compressed.

3. A peristaltic-type pump comprising, a housing having a pair of parallel spaced wall portions each of which is configured for defining a circular track, said tracks having their central axes co-axial and perpendicular to said wall portions, a plurality of planetary rollers extending axially of said circular tracks and having their opposite end portions in respective rolling engagement with the tracks, a central roller co-axial with said axes and in simultaneous engagement with all of said planetary rollers thereby to co-operate with said tracks for driving the planetary rollers about their respective central axes and along a circular path described by movement of the last mentioned axes, each of said rollers having a tube contacting portion intermediate said end portions, spider plate means in engagement with respective planetary rollers thereby to maintain the latter in substantial uniform spaced relation, said housing including a portion provided with a generally semi-cylindrical bearing surface which has its central axis co-axial with the central axes of said tracks, a length of collapsible tubing having a section thereof curved and in contact with said bearing surface along the length of the latter, which bearing surface has a radius greater than the sum of the radius of said path and the radius of one of said planetary rollers at the tube contacting portion thereof by an amount which is generally the same as twice the wall 6 thickness of said tubing, whereby successive portions of the tubing section are momentarily compressed by said planetary rollers upon rotation of the latter.

4. The pump according to claim 3 wherein said last mentioned housing portion is removably secured to said wall portions for being removed in a plane perpendicular to the axes of the planetary rollers, thereby to permit the pump to be readily attached to and detached from said tubing.

5. A peristalt-ic type pump comprising, a housing including a pair of parallel spaced wall portions, each of which is provided with an opening defining a circular track, said openings being of substantially the same diameter and having their central axes co-axial, a plurality of planetary rollers extending axially of said openings and having their opposite end portions in respective rolling engagement with said tracks, each of said planetary rollers being provided with a central axially extending bore, a central roller having its central axis co-axial with said axes and being in simultaneous rolling engagement with all of said planetary rollers, spider plate means having pins rotatably received in the bores of respective planetary rollers thereby to maintain the latter in substantial uniform spaced relation for rotation about their own axes and in a circular path defined by said tracks and the cylindrical surface of the central roller, said housing including a central portion disposed between said wall portions and provided with a bearing surface forming a segment of an imaginary cylinder having its central axis co-axial with the central axes of said openings, a length of collapsible tubing having a lengthwise section thereof in contact with said bearing surface along a portion of the length of the latter, which surface has a radius greater than the radii of said tracks by an amount which is generally the same as twice the wall thickness of said tubing, whereby successive portions of said tubing section are momentarily compressed by said planetary rollers upon rotation of the latter.

6. The perstaltic-type pump according to claim 5 wherein said central roller is provided with friction ring means simultaneously engageable with all of said plane-tary rollers thereby substantially to prevent slippage between the latter and the central roller.

7. A peristaltic-type pump comprising, a housing including a pair of walls and means for holding the walls in parallel spaced relation, each of said walls being provided with an opening defining a circuar track, said openings being of substantially the same diameter and having their central axes co-axial, at least three planetary rollers extending axially of said openings and having their opposite end portions in respective rolling engagement with said tracks, each of said planetary rollers being provided with a central axially extending bore, a central roller having its central axis co-axial with said axes and being in simultaneous rolling engagement with all of said planetary rollers, spider plate means having pins rotatably received in the bores of respective planetary rollers thereby to maintain the latter in substantial uniform spaced relation for rotation about their own axes and in a circu lar path defined by said track and the cylindrical surface of the central roller, a housing member removably secured between said walls and provided with a generally semi-cylindrical bearing surface which has its central axis co-axial with the central axis of said openings, a length of collapsible tubing having a lengthwise section thereof in contact with said bearing surface along a portion of the length of the latter, which bearing surface has a radius greater than the radii of said tracks by an amount which is generally the same as twice the wall thickness of said tubing, whereby successive portions of said tubing are momentarily compressed by said planetary rollers upon rotation of the latter.

8. The peristaltic-type pump according to claim 7 wherein said spider plates have marginal portions adapted for abutting engagement withrespective Walls for pre- Referencesflited by the Examiner venting separation of the rollers from the housing. UNITED STATES PATENTS 9. The pump according to claim 1 wherein said cen- V tral roller includes an axially extending shaft with 0p- 2899904 8/1959 Becker 7 103 149 posite ends of the latter extending beyond said Wall por- 5 tions of the pump, whereby said pump may be readily MARK NEWMAN Prlmary Examiner coupled with a like pump for being driven by .a power WARREN E. COLEMAN, Examiner. source common to both pumps. 

1. A PERISTALTIC-TYPE PUMP FOR MOMENTARILY COMPRESSING SUCCESSIVE PORTIONS OF A LENGTH OF COLLAPSIBLE TUBING, SAID PUMP COMPRISING, A HOUSING HAVING A PAIR OF PARALLEL SPACED WALL PORTIONS EACH OF WHICH IS CONFIGURED FOR DEFINING A CIRCULAR TRACK, SAID TRACKS HAVING THEIR CENTRAL AXES CO-AXIAL AND PERPENDICULAR TO SAID WALL PORTIONS, A PLURALITY OF PLANETARY ROLLERS EXTENDING AXIALLY OF SAID CIRCULAR TRACKS AND HAVING THEIR OPPOSITE END PORTIONS IN RESPECTIVE ROLLING ENGAGEMENT WITH THE TRACKS, A CENTRAL ROLLER CO-AXIAL WITH SAID AXES AND IN SIMULTANEOUS ENGAGEMENT WITH ALL OF SAID PLANETARY ROLLERS THEREBY TO COOPERATE WITH SAID TRACKS FOR DRIVING THE PLANETARY ROLLERS ABOUT THEIR RESPECTIVE CENTRAL AXES AND ALONG A CIRCULAR PATH DESCRIBED BY MOVEMENT OF THE LAST MENTIONED AXES, EACH OF SAID ROLLERS HAVING A TUBE CONTACTING PORTION INTERMEDIATE SAID END PORTIONS, SAID HOUSING INCLUDING A PORTION PROVIDED WITH A BEARING SURFACE WHICH EXTENDS ALONG AT LEAST A PORTION OF THE LENGTH OF SAID TRACKS IN PARALLEL SPACED RELATION FROM THE SAME, A LENGTH OF COLLAPSIBLE TUBING HAVING A SECTION THEREOF IN CONTACT WITH SAID BEARING SURFACE ALONG A PORTION OF THE LENGTH OF THE LATTER, THE RADIUS OF SAID BEARING SURFACE BEING GREATER THAN THE SUM OF THE RADIUS OF SAID PATH AND THE RADIUS OF ONE OF SAID PLANETARY ROLLERS AT THE TUBE CONTACTING PORTION THEREOF BY AN AMOUNT WHICH IS GENERALLY THE SAME AS TWICE THE WALL THICKNESS OF THE COLLAPSIBLE TUBING TO BE COMPRESSED. 